Tackling climate change requires to decarbonize all energy applications. To that end, producing hydrogen from low-carbon electricity and water by means of water electrolysis is garnering increasing attention. Hydrogen can indeed be used directly or further synthetized into chemical compounds that replace fossil fuels, hence providing a solution to address energy applications ill-suited for direct electrification. This concept, coined as power-to-X (PtX), remains yet in a formative phase characterized by high uncertainty. This paper takes on a technological innovation system (TIS) approach to examining the development of PtX in Europe. TIS surmises that technology diffusion is influenced by the structures of the socio-technical system it is part of and by how the latter functions. The case study engages TIS with the complexity of multi-sectoral, multi-purpose technology and explores the incorporation of social network analysis to scrutinize application configuration. The paper finds that the European PtX-TIS is growing and shows early signs of system building motor of innovation. However, the analysis also suggests that the lack of market formation and the underlying conflicts of interest across its wide actors' basis might jeopardize its future development. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.